Upholstery

I have original seats and the vinyl was in great condition only really dirty. so I scrubbed with oxyclean. Then I took out the one side with fabric. The original fabric was covered with the ugly 80's fabric but original was trashed. The foam was compressed after 49 years of being sat upon. I figured I would try to revive before spending the time to cut new foam.

TRICK: Steam! I have a professional steamer and I steamed the foam look at how the foam popped back into its original shape. I would not suggest using your iron foam will melt. you could put a sheet between but a small steamer would work plus you can steam your clothes.

SEATS: I took out the one side of fabric and applied the new fabric on top of original that also had foam in it so I steamed that back into shape after I sewn cushion back together. 
Sewing upholstery I highly recommend an industrial walking foot machine. I used 69 thread.
 Silly me forgot to take photos of that process. 

Curtains: I used a top sheet for lining. You could go buy curtain lining but it only comes in white that is why I used a 300 thread count sheet, better color selection. I used a soft sage green. You don't want your curtains to get sun rot. Especially vintage fabric. Plus the lining helps with insulation and with the darkening of windows when curtains are closed. 
I appen to have a rod across my trailer for privacy so I made a curtain that also went on top of counter when closed.